June 2015: a little above average, very dry

June finished hot in complete contrast to the opening few days which were a continuation of a disappointing May.station

There were six occasions when the maximum exceeded 25C – the highest being 30.8C on 30th, the warmest June day for four years.

Mean temperature for the month was 16.9C, 0.8C above the 1981-2010 mean. Rainfall of 17.5mm was 34% of average – the last three Junes have been notably dry.

There were 189.5 hours of sunshine recorded in this area which is 106% of what we can expect to see during an average June. The wettest day occurred on the 20th with 11.1mm. There were two days of thunder recorded.

So what has July got in store weatherwise? The models this morning (July 1st) suggest a battleground between Atlantic cooler air and hot continental air, a common feature at this time of year. The persistent heat on the continent looks like it will waft back and forth across the south-east – creating the risk of thundery downpours as it meets resistance from successive cold fronts.

Just 17.5mm of rain fell in June - 34% of average
Just 17.5mm of rain fell in June – 34% of average

The model output suggests the Atlantic air will eventually win through, allowing more changeable conditions in a week’s time. There is also a signal that high pressure will re-establish with a return to fine and very warm weather. As things stand the models remain finely balanced.

In contrast to the models my long range method suggests overwhelmingly that we are in for a warm July, up to 1.7C above average, at 60% probability

The next highest chance is for rather warm at 40% probability. If you add the probabilities together the chance of a rather warm to warm July can be put at 100% – perhaps a repeat of last year’s and 2013’s classic July is about to unfold?

Rainfall is looking below average, at 60% probability. There’s obviously a risk here that a couple of direct hits from thunderstorms would see the monthly total exceeded. I don’t have enough data to estimate sunshine but I would guess average to slightly above.

My June outlook was only good in that it ruled out any chance of a very warm month – the final mean was rather higher than I thought. I was also out with the very low rainfall – the signal was for something average. Sunshine was broadly average as I’d estimated

The Heronry Pond in Wanstead Park is suffering low water levels again
The Heronry Pond in Wanstead Park is suffering from low water levels again

Full stats for the month here: http://1drv.ms/1rSfT7Y

Here follows the full weather diary for June…

1st Sunny, bright start quickly turned cloudy with intermittent drizzle through the day. Turned windy at 6pm and was really blowing around midnight.
2nd Drizzle in the wind at obs time and very windy, wind only decreasing by evening. A dreadful day though warm.
3rd Sunny start though cloud gradually increased. Feeling humid and summery at last.
4th Sunny start with cloud dotted with alto cumulus and cirrus. Rain between 5am and 6am – though storms passed to our west and east.
5th Bright start after earlier rain – the thunderstorms seemed to pass to our west and east. Very humid and felt oppresive in the morning.
6th Sunny start with cloud bubbling up. Much cooler and fresher feel. Lots of long sunny spells.
7th Sunny, gin clear start. Just a few fair weather cumulus all day. Gorgeous.
8th Bright start though alto cumulus shaded early sun. Variable cumulus after that – feeling chilly.
9th Cloudy and brisk wind from NE. Feeling chilly.
10th Bright start with sunny intervals throughout the day.
11th Sunny start with few cirrus, sky then completely cleared.
12th Sunny start though cloud bubbled up through the day – felt very close at sports day. Distant thunder heard at 8pm with light rain – much less than was threatened.
13th Cloudy start, mostly calm, still and dull – a real nothing day though some late brightness after 2pm pushed up the temperature briefly. Mild overnight with some light drizzle before obs time.
14th Drizzle in the wind up until 11pm and falling temp. Then a brief sunny interlude before it was cloudy again.
15th Cloudy start then briefly clearing before, at 1pm, more cloud appeared. Clear overnight allowing temp to fall until 4.10am but clouding over by morning – bright warm sunshine at 9am.
16th Sunny start but very cloudy at times. This continued all day – though the night was cloudier hence warmer.
17th Sunny start but with lots of cloud around.
18th Lots of long suuny spells but cooler than yesterday.
19th Cloudy up until 11.30pm and cooler. Broke to sunny spells and much warmer at 2pm.
20th Bright start though warm from started pushing through just before 1pm. Some sunny breaks but rain pushed in. Was in Cheltenham but Woodford Wells reported thunder:  Between 1650and 1730 12mm fell followed by a decreasing amount of 2.4mm up to 1814  all BST Two thunder claps at 1715 and 1728.
21st In Cheltenham it was a mostly cloudy day though with more sunny intervals after midday. Rain spread in just before midnight with more in the early hours.
22nd Cloudy start though with brief sunny break at 10am. Some drizzle 11.15am then drier with sunny intervals.
23rd Bright start. Cloud broke to give warm sunny spells .
24th Sunny periods after a rather cloudy start. Felt very warm in the sun during walk around London with Neil and family.
25th Sunny start though hazy cloud developed from 10.30am, rather obscuring the sun at times, though it was bright all day. 26th Warm till late into the evening – still 18C at 11pm.
26th Bright start though cloudy, broke to sunny spells and felt warmer than forecast.
27th Sunny start though with cloudier spells all through the day. A very warm evening.
28th Sunny start quickly became cloudy with rain turning up at noon during early lunch. This later cleared to sunny spells and a pleasant afternoon.
29th Sunny start though with high cloud obscuring the sun at times.
30th Sunny, gin clear all day. only ‘cloud’ was distant grass fire.

The 30th was wall-to-wall sunshine until late in the evening when alto-cumulus and cumulus were observed
The 30th was wall-to-wall sunshine until late in the evening when alto-cumulus and cumulus were observed

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